JPH0521537Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to a vibrator for underwater concrete.

[Prior art]

Until now, the general opinion has been that when placing underwater concrete such as underground continuous walls and cast-in-place piles, there is no problem even if a vibrator is not used.

[Problems to be solved by this idea]

Recently, it has been demonstrated that when concrete is placed using the above-mentioned method, the concrete may not wrap around uniformly due to the structure of the reinforcing cage and other objects buried at the same time.

Furthermore, when pouring concrete, the falling height decreases as it approaches the top of the concrete, which reduces the pushing force required to wrap around the concrete, resulting in slightly inferior quality near the top.

For these reasons, it has been proven that using a vibrator in combination with underwater concrete construction is more effective in terms of quality.

However, in order to use a vibrator, the vibrator must always maintain a certain depth from the top of the concrete. This will involve the slime and have the opposite effect.

For these reasons, it has been impossible to use conventional vibrators as they are for underwater concrete construction.

Therefore, this idea solves the above-mentioned problems by automatically raising the vibrator as the concrete placement surface rises, and by always inserting the vibrator vertically into the concrete and placing it at a predetermined position from the top of the concrete. An object of the present invention is to provide a vibrator for underwater concrete that can maintain a vibrating part in position.

[Structure of the idea]

The vibrator for underwater concrete according to this invention has an upper rod part that is suspended and supported from an excavation opening so as to be able to rise and fall freely, and a vibrator excitation part that is attached to the lower end of this part via a vibration insulator. is characterized by providing a buoyant force so that the vibration generating part of the vibrator is always at the optimum vibration position in the concrete, and is equipped with a guide which is cylindrical and has a truncated cone shape with tapers at the upper and lower ends.

〔Example〕

Hereinafter, the invention will be explained using the illustrated embodiments. The attached drawing shows a schematic diagram of the case where the vibrator of this invention is adopted for the construction of cast-in-place piles.

Here, at the excavation opening, there is a cable reel operation panel 9 that allows the cable 10 to be arbitrarily fed out and retracted.
is provided, and the upper rod portion 1 of the vibrator is attached to the tip of this cable 10.

Furthermore, a vibrator oscillating part 3 is attached to the lower end of the upper rod part 1 via a vibration insulator 2. The vibrator oscillating unit 3 is configured to be supplied with the necessary power from the ground via a separately provided power cable (not shown), vibrate with the vibration insulator 2 as a base, and give vibration to the surrounding concrete 5. has been done.

Further, the upper rod portion 1 is provided with cylindrical guides 4, 4 that fit into the inner space of the reinforcing bar cage 8. The guides 4, 4 have a float function to adjust their levitation, and the upper and lower ends of the guides 4, 4 are formed into a tapered truncated cone shape in order to be able to move up and down within the reinforcing bar cage 8. ing.

The appropriate float capacity of the guides 4, 4 is determined from the difference in specific gravity between the stabilizer liquid 7 and the concrete 5 on the concrete placement surface and the shape of the vibrator.

By balancing the vibrator's own weight, the resultant force of the penetration force during vibration, and the buoyant force, a constant length can always be embedded in the concrete 7.

Further, in order to prevent the weight of the cable 10 and the vibrator from falling down, a constant tension is always applied to the cable 10 from the cable reel operation panel 9 on the ground. However, the tension is such that it does not wind up the vibrator itself.

That is, F = buoyancy force, T = cable tension, P =
When the vibrator's own weight + penetration force is used, it is desirable to maintain the relationship F+T≧P.

In order to increase the buoyancy, adjust the length of the guides 4, 4, and conversely, if it is necessary to increase the weight, install weights on the guide parts 4, 4 of the upper rod part 1, and adjust the length of the vibrator oscillating part 3. is inserted and maintained in the concrete for a predetermined length from the top surface of the concrete.

In this embodiment, two guides 4 are used, but they can be adjusted as appropriate depending on the required buoyancy and construction conditions, and can also be used for cast-in-place piles, underground continuous walls, etc.

[Effect of idea]

This idea consists of the above-mentioned structure, and an upper rod part is provided on the top of the vibrator's excitation part to give buoyancy, and a truncated cone-shaped guide with a cylindrical shape and tapered upper and lower ends is attached, so that reinforcing steel is used. The vibrator can be lowered reliably into the cage, and the vibrator can be automatically floated up as the concrete placement surface rises, and the vibrator is always inserted vertically into the concrete and placed at a predetermined position from the top of the concrete. This is a vibrator for underwater concrete that can maintain the vibrating part.

Furthermore, the number of guides can be appropriately selected or a weight can be mounted on the guide section to easily adjust the levitation.

[Brief explanation of the drawing]

The drawings are schematic illustrations of embodiments. 1... Upper rod part, 2... Vibration insulator, 3...
... Vibrator excitation part, 4... Guide, 5... Concrete, 6... Slime part, 7... Stabilizing liquid,
8...Reinforced cage, 9...Cable reel operation panel, 1
0...Cable.

Claims (1)

[Scope of utility model registration request] A hibrator for underwater concrete,
an upper rod part suspended and supported so as to be able to rise and fall freely into the excavation part from the excavation opening; a vibrator vibration generating part attached to the lower end of the upper rod via a vibration insulator; A vibrator for underwater concrete, which provides buoyancy so that the vibrator vibration generating part is always at an optimal vibration position in concrete, and is provided with a cylindrical guide having a truncated cone shape with tapered upper and lower ends.